This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Redox scanning can measure the in vivo mitochondrial redox states of tissues on the basis of the fluorescence signals of NADH and Fp (oxidized flavoproteins), and Fp redox ratios (Fp/(NADH+Fp)) was shown by previous studies to predict the aggressiveness of human melanoma and breast cancer in mouse xenografts. Redox ratio is also sensitive to cellular processes including apoptosis, differentiation and metabolism. In this project we employ redox scanning to study human lymphoma cell culture and mouse xenografts with and without chemotherapy. We hope to understand more about the role of mitochondrial redox state in tumor progression and response to treatment. We may also accumulate evidence for targeting mitochondrial redox state as a novel approach of cancer therapy.